Patents by Inventor Deepak A. Ramappa
Deepak A. Ramappa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20110204264Abstract: Ions are generated and directed toward a workpiece. A laser source generates a laser that is projected above the workpiece in a line. As the laser is generated, a fraction of the ions are blocked by the laser. This may enable selective implantation or modification of the workpiece. In one particular embodiment, the lasers are generated while ions are directed toward the workpiece and then stopped. Ions are still directed toward the workpiece after the lasers are stopped.Type: ApplicationFiled: February 25, 2010Publication date: August 25, 2011Applicant: VARIAN SEMICONDUCTOR EQUIPMENT ASSOCIATES, INC.Inventor: Deepak A. RAMAPPA
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Publication number: 20110201176Abstract: A method of cleaving a substrate is disclosed. A species, such as hydrogen or helium, is implanted into a substrate to form a layer of microbubbles. The substrate is then annealed a pressure greater than atmosphere. This annealing may be performed in the presence of the species that was implanted. This diffuses the species into the substrate. The substrate is then cleaved along the layer of microbubbles. Other steps to form an oxide layer or to bond to a handle also may be included.Type: ApplicationFiled: August 5, 2010Publication date: August 18, 2011Applicant: VARIAN SEMICONDUCTOR EQUIPMENT ASSOCIATES, INC.Inventors: Deepak RAMAPPA, Julian G. Blake
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Publication number: 20110151610Abstract: Methods to texture or fabricate workpieces are disclosed. The workpiece may be, for example, a solar cell. This texturing may involve etching or localized sputtering using a plasma where a shape of a boundary between the plasma and the plasma sheath is modified with an insulating modifier. The workpiece may be rotated in between etching or sputtering steps to form pyramids. Regions of the workpiece also may be etched or sputtered with ions formed from a plasma adjusted by an insulating modifier and doped. A metal layer may be formed on these doped regions.Type: ApplicationFiled: December 23, 2009Publication date: June 23, 2011Applicant: VARIAN SEMICONDUCTOR EQUIPMENT ASSOCIATES, INC.Inventors: Deepak A. RAMAPPA, Ludovic Godet
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Publication number: 20110127885Abstract: An improved process of substrate cleaving and a device to perform the cleaving are disclosed. In the traditional cleaving process, a layer of microbubbles is created within a substrate through the implantation of ions of a gaseous species, such as hydrogen or helium. The size and spatial distribution of these microbubbles is enhanced through the use of ultrasound energy. The ultrasound energy causes smaller microbubbles to join together and also reduces the straggle. An ultrasonic transducer is acoustically linked with the substrate to facilitate these effects. In some embodiments, the ultrasonic transducer is in communication with the platen, such that ultrasound energy can be applied during ion implantation and/or immediately thereafter. In other embodiments, the ultrasonic energy is applied to the substrate during a subsequent process, such as an anneal.Type: ApplicationFiled: January 28, 2011Publication date: June 2, 2011Applicant: VARIAN SEMICONDUCTOR EQUIPMENT ASSOCIATES, INC.Inventor: Deepak A. RAMAPPA
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Publication number: 20110124186Abstract: A plasma processing apparatus comprises a plasma source configured to produce a plasma in a plasma chamber, such that the plasma contains ions for implantation into a workpiece. The apparatus also includes a focusing plate arrangement having an aperture arrangement configured to modify a shape of a plasma sheath of the plasma proximate the focusing plate such that ions exiting an aperture of the aperture arrangement define focused ions. The apparatus further includes a processing chamber containing a workpiece spaced from the focusing plate such that a stationary implant region of the focused ions at the workpiece is substantially narrower that the aperture. The apparatus is configured to create a plurality of patterned areas in the workpiece by scanning the workpiece during ion implantation.Type: ApplicationFiled: November 16, 2010Publication date: May 26, 2011Applicant: VARIAN SEMICONDUCTOR EQUIPMENT ASSOCIATES, INC.Inventors: Anthony Renau, Ludovic Godet, Timothy J. Miller, Joseph C. Olson, Vikram Singh, James Buonodono, Frank Sinclair, Deepak A. Ramappa, Russell Low, Atul Gupta, Kevin M. Daniels
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Publication number: 20110104618Abstract: Various methods of utilizing the physical and chemical property differences between amorphized and crystalline silicon are used to create masks that can be used for subsequent implants. In some embodiments, the difference in film growth between amorphous and crystalline silicon is used to create the mask. In other embodiments, the difference in reflectivity or light absorption between amorphous and crystalline silicon is used to create the mask. In other embodiments, differences in the characteristics of doped and undoped silicon is used to create masks.Type: ApplicationFiled: November 1, 2010Publication date: May 5, 2011Applicant: VARIAN SEMICONDUCTOR EQUIPMENT ASSOCIATES, INC.Inventors: Nicholas P.T. Bateman, Helen L. Maynard, Benjamin B. Riordon, Christopher R. Hatem, Deepak Ramappa
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Publication number: 20110097840Abstract: Methods of improving the anti-reflection properties of one or more dielectric layers and reducing surface recombination of generated carriers of a solar cell are disclosed. In some embodiments, dopants are introduced into the dielectric layers to improve their anti-reflection properties. In other embodiments, species are introduced into the dielectric layers to create electrical fields which repel the minority carriers away from the surface and toward the contacts. In another embodiment, mobiles species are introduced to the anti-reflective coating, which cause carrier to be repelled from the surface of the solar cell. By creating a barrier at the surface of the solar cell, undesired recombination at the surface may be reduced.Type: ApplicationFiled: October 25, 2010Publication date: April 28, 2011Applicant: VARIAN SEMICONDUCTOR EQUIPMENT ASSOCIATES, INC.Inventor: Deepak A. Ramappa
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Patent number: 7910477Abstract: Methods for forming dual damascene interconnect structures are provided. The methods incorporate an ashing operation comprising a first ash operation and a second overash operation. The ashing operation is performed prior to etching of an etch stop layer. The operation removes residue from a cavity formed during formation of the interconnect structure and facilitates better CD control without altering the cavity profiles.Type: GrantFiled: December 28, 2007Date of Patent: March 22, 2011Assignee: Texas Instruments IncorporatedInventors: Jeannette Michelle Jacques, Deepak A. Ramappa
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Patent number: 7902091Abstract: An improved process of substrate cleaving and a device to perform the cleaving are disclosed. In the traditional cleaving process, a layer of microbubbles is created within a substrate through the implantation of ions of a gaseous species, such as hydrogen or helium. The size and spatial distribution of these microbubbles is enhanced through the use of ultrasound energy. The ultrasound energy causes smaller microbubbles to join together and also reduces the straggle. An ultrasonic transducer is acoustically linked with the substrate to facilitate these effects. In some embodiments, the ultrasonic transducer is in communication with the platen, such that ultrasound energy can be applied during ion implantation and/or immediately thereafter. In other embodiments, the ultrasonic energy is applied to the substrate during a subsequent process, such as an anneal.Type: GrantFiled: August 11, 2009Date of Patent: March 8, 2011Assignee: Varian Semiconductor Equipment Associates, Inc.Inventor: Deepak A. Ramappa
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Patent number: 7868306Abstract: A method for ion implantation is disclosed which includes modulating the temperature of the substrate during the implant process. This modulation affects the properties of the substrate, and can be used to minimize EOR defects, selectively segregate and diffuse out secondary dopants, maximize or minimize the amorphous region, and vary other semiconductor parameters. In one particular embodiment, a combination of temperature modulated ion implants are used. Ion implantation at higher temperatures is used in sequence with regular baseline processing and with ion implantation at cold temperatures. The temperature modulation could be at the beginning or at the end of the process to alleviate the detrimental secondary dopant effects.Type: GrantFiled: October 2, 2008Date of Patent: January 11, 2011Assignee: Varian Semiconductor Equipment Associates, Inc.Inventor: Deepak A. Ramappa
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Publication number: 20100323113Abstract: A method of using ion implantation techniques to create graphene is disclosed. Carbon ions are implanted in a substrate, such as a metal foil, using a plasma doping system or a beam line implanter. The implant is performed at an elevated temperature, to allow a large number of carbon ions to be absorbed by the foil. As the temperature is reduced, the excessive number of carbon atoms causes the foil to be saturated, and the carbon atoms diffuse to the surface, thereby producing graphene. In another embodiment, a plasma doping system is used, where a plasma containing carbon and other species is created. These additional species are also implanted, thereby causing the diffused atoms to contain both carbon and the additional species.Type: ApplicationFiled: June 18, 2009Publication date: December 23, 2010Inventors: Deepak A. Ramappa, Paul Sullivan
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Formation Of Raised Source/Drain On A Strained Thin Film Implanted With Cold And/Or Molecular Carbon
Publication number: 20100279479Abstract: A method is disclosed for enhancing tensile stress in the channel region of a semiconductor structure. The method includes performing one or more cold-carbon or molecular carbon ion implantation steps to implant carbon ions within the semiconductor structure to create strain layers on either side of a channel region. Raised source/drain regions are then formed above the strain layers, and subsequent ion implantation steps are used to dope the raised source/drain region. A millisecond anneal step activates the strain layers and the raised source/drain regions. The strain layers enhances carrier mobility within a channel region of the semiconductor structure, while the raised source/drain regions minimize reduction in strain in the strain layer caused by subsequent implantation of dopant ions in the raised source/drain regions.Type: ApplicationFiled: May 1, 2009Publication date: November 4, 2010Applicant: Varian Semiconductor Equipment Associates, Inc.Inventors: Christopher R. Hatem, Helen L. Maynard, Deepak A. Ramappa -
Patent number: 7772867Abstract: A method for detecting defects during semiconductor device processing can include providing a substrate having a semiconductor comprising layer with electrically isolated application and test circuits are formed thereon, directing an electron current inducing beam to the test circuit; measuring a current between the first and the second contact pads in the test circuit; determining an electron beam induced current (EBIC); and identifying one or more defect locations in the test circuit based on the EBIC and a location of the electron beam corresponding to the EBIC. A test circuit can include a plurality of semiconductor devices connected in parallel, a first contact pad coupled to a first terminal of the semiconductor devices, and at least a second contact pad coupled to a substrate terminal associated with the semiconductor devices.Type: GrantFiled: February 26, 2008Date of Patent: August 10, 2010Assignee: Texas Instruments IncorporatedInventors: Richard L. Guldi, Toan Tran, Deepak A. Ramappa
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Patent number: 7767583Abstract: Embodiments of this method improve the results of a chemical mechanical polishing (CMP) process. A surface is implanted with a species, such as, for example, Si, Ge, As, B, P, H, He, Ne, Ar, Kr, Xe, and C. The implant of this species will at least affect dishing, erosion, and polishing rates of the CMP process. The species may be selected in one embodiment to either accelerate or decelerate the CMP process. The dose of the species may be varied over the surface in one particular embodiment.Type: GrantFiled: December 10, 2008Date of Patent: August 3, 2010Assignee: Varian Semiconductor Equipment Associates, Inc.Inventors: Deepak Ramappa, Thirumal Thanigaivelan
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Patent number: 7745238Abstract: A method of measuring temperature across wafers during semiconductor processing includes the step of providing a correlation between a peak wafer temperature during a processing step and a change in wafer surface charge or surface potential following the processing step. A first wafer to be characterized for its peak temperature spatial distribution during the processing step is processed through the processing step. The wafer surface charge or surface potential at a plurality of locations on the first wafer are measured following the processing step. A peak temperature spatial distribution for the first wafer is then determined based on the correlation and the wafer surface charge or surface potential measured in the measuring step.Type: GrantFiled: February 26, 2008Date of Patent: June 29, 2010Assignee: Texas Instruments IncorporatedInventors: Deepak A. Ramappa, Rosa A. Orozco-Teran, Laura Matz
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Publication number: 20100155909Abstract: Methods of improving charge trapping are disclosed. One such method includes forming an oxide-nitride-oxide tunnel stack and a silicon nitride layer on the oxide-nitride-oxide tunnel stack. This silicon nitride layer is implanted with ions. These ions may function as electron traps or as fields. The silicon nitride layer may be part of a flash memory device.Type: ApplicationFiled: December 17, 2009Publication date: June 24, 2010Applicant: VARIAN SEMICONDUCTOR EQUIPMENT ASSOCIATES, INC.Inventors: Deepak RAMAPPA, Kyu-Ha SHIM
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Publication number: 20100136781Abstract: One embodiment of the present invention relates to a photolithography mask configured to form a metallization and via level utilizing a single lithography and etch process. More particularly, a photolithography mask comprising a mask via shape and one or more metal wire shapes is configured to produce both on-wafer metal lines and via levels. The mask via shape corresponds to an on-wafer photoresist via opening having a first critical dimension (CD). The one or more mask wire shapes correspond to one or more on-wafer photoresist wire openings respectively having a second CD. The first CD is larger than the second CD thereby providing a greater vertical etch rate for ILD exposed by the photoresist via opening than for ILD exposed by the one or more photoresist wire openings. This difference in CD results in a via extending vertically below the metal wire level, thereby making physical contact with underlying metal.Type: ApplicationFiled: December 3, 2008Publication date: June 3, 2010Applicant: Texas Instruments IncorporatedInventors: Makarand R. Kulkarni, Deepak A. Ramappa
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Publication number: 20100110239Abstract: Dark currents within a photosensitive device are reduced through improved implantation of a species during its fabrication. Dark currents can be caused by defects in the photo-diode device, caused during the annealing, implanting or other processing steps used during fabrication. By amorphizing the workpiece in the photo-diode region, the number of defects can be reduced thereby reducing this cause of dark current. Dark current is also caused by stress induced by an adjacent STI, where the stress caused by the liner and fill material exacerbate defects in the workpiece. By amorphizing the sidewalls and bottom surface of the trench, defects created during the etching process can be reduced. This reduction in defects also decreases dark current in the photosensitive device.Type: ApplicationFiled: October 28, 2009Publication date: May 6, 2010Inventors: Deepak Ramappa, Dennis Rodier
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Publication number: 20100112788Abstract: A method of implantation that minimizes surface damage to a workpiece is disclosed. In one embodiment, following a doping implant, a second implant is performed which causes the silicon at the surface of the workpiece to become amorphous. This reduces surface damage and interstitials, which has several benefits. First, inactive dopant clusters may become activated due to the replenishment of silicon. Secondly, the amorphous nature of the silicon makes it bond more easily in subsequent process steps, such as silicidation.Type: ApplicationFiled: October 22, 2009Publication date: May 6, 2010Inventor: Deepak Ramappa
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Publication number: 20100084580Abstract: A method for ion implantation is disclosed which includes modulating the temperature of the substrate during the implant process. This modulation affects the properties of the substrate, and can be used to minimize EOR defects, selectively segregate and diffuse out secondary dopants, maximize or minimize the amorphous region, and vary other semiconductor parameters. In one particular embodiment, a combination of temperature modulated ion implants are used. Ion implantation at higher temperatures is used in sequence with regular baseline processing and with ion implantation at cold temperatures. The temperature modulation could be at the beginning or at the end of the process to alleviate the detrimental secondary dopant effects.Type: ApplicationFiled: October 2, 2008Publication date: April 8, 2010Inventor: Deepak A. Ramappa